Hydroponics is the process of growing plants in a soil-less mixture of water and nutrients. While researchers published early manuscripts on soil-less growing methods in the early 17th century, it wasn’t until 300 years later that we cracked hydroponic systems. University of California researcher William Frederick Gericke is credited with inventing modern hydroponics in 1929. He coined the term ‘hydroponics’ in 1937.
BENEFITS OF HYDROPONICS
Humans have been successfully cultivating plants in soil for thousands of years, so why change now? Well, hydroponics is the next step from soil cultivation. In fact, hydroponics offers the following five main benefits over traditional soil culture:
Studies have found that hydroponically grown plants grow 20% to 50% faster than their soil grown counterparts. In human terms, that’d be like getting to six feet tall in 5th grade. This means that gardeners can fit more rotations into a single growing season.
Greater yields per plant
Not only do plants grown hydroponically experience faster vegetative growth, they also produce more, and larger, fruits, roots, and flowers.
More efficient use of water and nutrients
Hydroponic systems recycle water and nutrients, instead of losing them in the form of runoff and evaporation. While not an entirely closed loop system, it is a whole lot more efficient than traditional soil farming.
More efficient use of space
In a traditional soil system, plants need lots of soil to hold enough moisture, nutrients, and oxygen for their root systems. With hydroponic systems, roots are more compact and efficient in an environment controlled specifically for moisture, nutrients, and oxygen. Because of this, hydroponic systems have been incredibly important to the surge in urban farming, rooftop farming, and even farming in space.
Limited exposure to, and greater control over, pests and disease
While soil harbors many goodies that plants like, it can also harbor fungus, bacteria, viruses, and plant-killing pests. A hydroponic nutrient solution, on the other hand, is tuned to a plant’s needs and not the needs of diseases and pests. Even in situations where a hydroponic system does get exposed to a pest or disease, flushing the system and adding defenses like fungicides is much easier and quicker.
It is for the above five reasons that organizations like NASA invest heavily in hydroponic systems and techniques. To grow plants in space, you need advanced systems that can efficiently convert limited resources and space into edible crops and oxygen. And hydroponics fits the bill. But it’s not just astronauts that benefit from hydroponics. In recent years, we have witnessed an explosion in hydroponic technologies and techniques. Now, everyone from hobbyists to commercial gardeners are growing food, herbs, and flowers without an ounce of soil.
WHAT DO YOU NEED TO GET STARTED?
You’ll need five things to grow your first hydroponic crop. These are:
- A hydroponic system (huh, really?)
- A light source
- A growing medium
Keep reading below to see your options for each of these.
HOW MUCH DOES IT COST?
At this point, you may be thinking that if NASA uses hydroponic systems, the price tag must be in the millions of dollars. That’s not the case (even for them). Hacking together a simple hydroponic system costs less than $50. However, like many hobbies, once you get started, you’ll want to add to, and optimize, your system. And the sky is the limit with hydroponics. You’ll find plenty of options for advanced lighting, nutrient, and watering systems. Like any great hobby, hydroponics is easy and cheap to get started with. But it still gives you the option to drop $1000’s to the dismay of your significant other. Not that we’d know anything about that personally…
TYPES OF HYDROPONIC SYSTEMS
There are six main types of hydroponic systems. Each functions with the same concept in mind: get the right amount of nutrient enriched water to the roots of a plant. Too much and roots suffer from a lack of oxygen and the plant can quickly die. Too little and roots can dry out, stunting growth. In order of least complex to most complex, the six most common systems are:
Overview: The simplest hydroponic systems use wicks to move nutrient solution towards plants’ roots. Wick systems use no moving parts and no electricity, instead relying on capillary action to move the solution against gravity. For this reason, they are often the first hydroponic system that people try out. And while they can produce faster growth than a soil bed and a watering can, wick hydroponic systems can’t compete with the more complex systems below. The simplest addition to improve a wick system is to put an air stone in the reservoir to better oxygenate the nutrient solution. Even then, a wicks can only move so much nutrient solution and generally rely on the growing medium to trap moisture. The result is a system that is hard to fine tune to the plant you are growing.
Maintenance: As wick systems have no moving parts, you don’t have to ever worry about pumps or nozzles getting clogged. The biggest thing to watch with a wick system is that soil moisture levels stay within safe limits for your plants. Having too big a wick, or too many wicks, can keep your soil over-saturated with nutrient solution, leading to rot and disease.
Overview: The drip system is the wick system’s bigger brother. Both work on the same principle of moving nutrient solution from a lower reservoir to a plants’ roots. However, a drip system is an active system, meaning it uses electricity and moving parts. Drip systems pump nutrient solution through small-diameter tubing. The tubing runs along the plants, with a small drip nozzle at the base of each. As electric pumps can continuously move large quantities of nutrient solution, growing medium can be more porous than in a passive wick system, meaning roots can stay better oxygenated and are less likely to rot.
Maintenance: Generally, drip systems are relatively simple and require little maintenance. As with any system, you will need to regularly check your reservoir levels, PH levels, and nutrient concentrations. Depending on the size of the reservoir, this must be done every few days to every few weeks. In addition, you will need to check in on the system every every so often to ensure that roots are not clogging the overflow drain and that the water pump and/or drip nozzles are not clogged with nutrient sediment. Once you get comfortable with a drip system, maintenance is a breeze and you will be able to tell if anything is wrong withe the system with just a quick glance.
Deep Water Culture
Overview: Deep water culture (DWC) systems rely on a simple principle: instead of providing water to roots suspended in air, DWC systems provide air to roots suspended in water. An air pump, similar to ones used in fish tanks, pumps air to an air stone. The air stone disperses and dissolves the oxygen into the nutrient solution.
Maintenance: In general, DWC systems are cheap and simple. As with any system, you will need to regularly check nutrient and PH levels in your reservoir. As roots must stay submerged at all times, it is vital to keep an eye on reservoir levels. Many systems come with a water level meter so that you can check levels without opening the lid. It is also critical to to ensure that your plants’ roots are getting enough oxygen. If roots don’t get adequate oxygen, they begin to rot. You’ll figure this out quickly due to the “root rot” smell. As oxygen is the name of the game in DWC, it always is good to error on the side of having too much rather than not enough. One major maintenance benefit of DWC is the fact that moving parts are kept far from plants and thus can’t get clogged with roots.
Ebb and Flow (Flood and Drain)
Overview: As you’ve probably figured out by now, hydroponics is all about delivering oxygen, nutrients, and water to plants roots at the right ratio. Some systems, like drip and DWC, attempt to keep plants at the perfect ratio 100% of the time. Ebb and flow systems, also known as flood and drain systems, work in a different way. These systems switch between a flood cycle and a drain cycle. During the flood cycle, nutrient solution is pumped up from a reservoir to completely submerge roots. After a short time, the nutrient solution is allowed to drain. This cycle mimics heavy rain flooding a root system before draining back into the underground water table.
Maintenance: Ebb and flow systems are a bit more complex than the systems discussed above. A successful ebb and flow cycle requires pumps, valves, and timers all working together in unison. If any fails, the entire system fails. It is vital to keep the fill/drain fitting clear of roots and other debris and to ensure the pump is filling the growing tray completely. However, besides making sure everything is still running, ebb and flow systems require little upkeep. Unlike DWC, the reservoir only needs refilling when the level drops to the top of the pump. In addition, ebb and flow systems work very well at scale. One large water pump and a single fill/drain fitting can flood areas over a hundred square feet. A DWC system of the same size would need multiple air pumps and stones to ensure even distribution of dissolved oxygen.
Nutrient Film Technique
Overview: Nutrient film technique (NFT) mixes some of best of both ebb and flow and drip systems. Instead of dripping nutrient solution around the top of the plant, an NFT system pumps nutrient solution to the top of a “gutter” in which the plants’ roots are suspended. The nutrient solution then flows across all of the roots. The system mimics a rivers edge, where well oxygenated water constantly flows past a plants roots. As this method relies on gravity for the flow back to the reservoir, NFT systems can have multiple levels and are well suited for vertical farming. Unfortunately, starting plants in NFT systems isn’t possible until the roots are big enough to reach the nutrient solution. For this reason, some systems combine a secondary drip system or aeroponic spray system to allow starting plants.
Maintenance: NFT systems are one of the most difficult systems to get working perfectly. Setting the right shape and slope on the gutters is the difference between roots receiving a well-oxygenated stream of nutrient solution or drowning in a stagnant pool. However, once set up right, these systems require little maintenance and allow more plants per square foot than just about any other method. Similar to ebb and flow, a single water pump can move enough nutrient solution for dozens of plants.
Overview: Aeroponics is the new kid on the hydroponic block. While early attempts in labs across the world proved successful, aeroponics wasn’t introduced commercially until the 1980s. Aeroponics is the process of growing plants without any growing medium at all. Instead, the roots are directly misted with nutrient solution. While aeroponic systems can achieve incredible growth rates, they also are by far the most complex. There are a few types of aeroponic systems. The simplest aeroponic systems use small circular spraying nozzles placed below the roots. More complex systems use ultrasonic foggers to create nutrient fog that with particle sizes measured in microns. This nutrient fog is readily absorbed by roots. Tuning an aeroponic system is both difficult and takes a lot of knowledge. For this reason, we generally do not recommend aeroponic systems for newcomers.
Maintenance: Aeroponic systems rely on tight tolerances in order to generate the high pressures necessary to create mist and/or fog. Combining tight tolerances with dissolved solids means a lot of basic maintenance. Clearing clogged sprayer nozzles will almost always make its way onto the to-do list of an aeroponic grower. In addition, nutrient ultrasonic nutrient foggers require specialized materials that can hold up to the dissolved nutrients without wearing out early. While aeroponic systems require careful attention and maintenance, the payoff comes at harvest time. A well-maintained aeroponic system is the Ferrari of plant growing and no other system can match in terms of sheer growing ability.
Light Emitting Diode (LED)
Compact Fluorescent Lighting (CFL)
High Pressure Sodium (HPS)
Hetal Halide (MH)